Compact Light Source Device Using Wavelength Separation

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Solution Overview

Problem

Endoscope systems using semiconductor light sources require multiple color light sources to reproduce observation images, leading to increased device size and manufacturing costs due to the need for multiple light sources.

Innovation Solution

A light source device comprising a blue light source, a broadband green light source with a red component, and an optical filter that adjusts the green light's wavelength components, allowing for the omission of a dedicated red light source by adjusting the light amount ratio between green and red components to form white illumination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple color light sources (blue, green, red LEDs) are arranged to reproduce observation images, then color reproduction accuracy is improved, but device size and manufacturing cost increase

Engineering Contradiction:
Improvecolor reproduction accuracyVSAvoiddevice size
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts the red light component from the broadband green light emitted by the green LED, separating it to be used as the red light source. This eliminates the need for a dedicated red LED while maintaining color reproduction accuracy, thereby reducing device size and complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The green LED serves multiple functions: it provides the green light component for white light formation and simultaneously provides the red light component through wavelength separation. This multi-functionality reduces the total number of light sources needed while maintaining color reproduction capability

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Manufacturing precision

If multiple color light sources (blue, green, red LEDs) are arranged to reproduce observation images, then color reproduction accuracy is improved, but manufacturing cost increases

Engineering Contradiction:
Improvecolor reproduction accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent extracts the red light component from the broadband green light emitted by the green LED, separating it to be used as the red light source. This eliminates the need for a dedicated red LED while maintaining color reproduction accuracy, thereby reducing device size and complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The green LED serves multiple functions: it provides the green light component for white light formation and simultaneously provides the red light component through wavelength separation. This multi-functionality reduces the total number of light sources needed while maintaining color reproduction capability

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If light sources of various colors are provided to enhance observation image reproduction, then observation image quality is improved, but device size increases

Engineering Contradiction:
Improveobservation image qualityVSAvoiddevice size
Core Design Contradiction:
Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The patent extracts the red light component from the broadband green light emitted by the green LED, separating it to be used as the red light source. This eliminates the need for a dedicated red LED while maintaining color reproduction accuracy, thereby reducing device size and complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a wavelength separation dimension to the green light path, using optical filters to separate the red component from the green LED's broadband emission. This allows obtaining red light without adding a separate red LED, thus improving image quality while maintaining compact device size

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution results in a more compact and cost-effective light source device that produces white illumination suitable for imaging, matching the color tone of traditional lamp-based systems without the need for a separate red light source, thereby reducing device size and cost.

Implementation Method 1

an optical filter that adjusts an amount of the broadband green light for each wavelength. The optical filter has a characteristic in which the reflectance of the green component is smaller than the reflectance of the red component in the case of reflecting the broadband green light or a characteristic in which the transmittance of the green component is smaller than the transmittance of the red component in the case of transmitting the broadband green light

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

the second light source includes a light emitting element that emits excitation light and a fluorescent substance that emits the broadband green light when the excitation light is emitted thereto

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP3257432B1Light source device and endoscope system
Publication Date: 2023.05.10 FUJIFILM CORP
  • EP3257432B1 patent drawingFigure 1
  • EP3257432B1 patent drawingFigure 2
  • EP3257432B1 patent drawingFigure 3~4

AI summary

There are provided a light source device, which is more compact and inexpensive than a known light source device, and an endoscope system having a compact and inexpensive light source device. In a light source device, a light source unit includes a first light source that emits blue light, a second light source that emits broadband green light including not only a green component but also a red component, and an optical filter that adjusts the amount of broadband green light for each wavelength. The optical filter has a characteristic in which the reflectance of the green component is smaller than the reflectance of the red component in the case of reflecting the broadband green light or a characteristic in which the transmittance of the green component is smaller than the transmittance of the red component in the case of transmitting the broadband green light.